Improvement in dental engines



2 S-heets Sheet'L 6. M. CURTIS.

Dental Engines. No. 138,318, 7 Patent'edApr ill29,1873'.

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6.151. CURTIS.. Den-tal- Engines;

Patented April 29, 187' mimzsww @mnmntvu AM Pncm-umosRAm/c ca MK (assonna macsss) UNITED STATES PATENT QFrIoE.

CHARLES M. CURTIS, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN DENTAL ENGINE S.

Specification forming part of Letters Patent No. 138,318, dated April 29, 1873; application filed February 14, 1873. l

To all whom it may concern:

Be it known that I, CHARLES M. CURTIS, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Dental Engines, and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use it, reference being had to the accompanying drawing 'which forms part of this specification.

' Referring to the accompanying drawing,

Figure 1 is a longitudinal central sectional view of the hand-piece. Fig. 2 is a side view of the hand-piece. Fig. 3 are side views of the tool. Fig.4 is a side elevation of the base of dental engine. Fig.5 is a front view of the same. Fig. 6 is a plan view of the treadle and tripod. Fig. 7 is a side elevation of the engine complete. Fig. 8 is a side view of the upper portion of the flexible rod or shaft. Fig. 9 is a sectional view of the lower portion of the flexible rod or shaft.

My invention relates to an improved'form of dental burring-engine especially designed to assist in operations upon the natural teeth in the nionth. The nature of this invention may be briefly stated as consisting in the peculiar construction of a-continuous rotating rod or shaft, and its supports and attachments, communicating motion from a fly-wheel operated by the foot or other power to the tool, bywhich a great degree of flexure and mobility is obtained without undue friction, noise,

or loss of power, dispensingwith all cords, bands, and pulleys, and securin g a steady 0011- tinuous motion, by which many valuable and useful results are obtained, as will be hereinafter fully described and specially set forth. It relates also to the method of fastening the tool so that it will be held securely when in position in the hand-piece, and may be readily removed or changed without any risk to the tool itself or to the socket in which it fits.

- i The accompanying drawing represents this .improved dental engine A designates a tripod or stand, from which rises a suitable shaped and arranged standard, B, to which it is secured. G is a beveled fly-wheel, fixed to the shaft E, whichpasses through bearings in the standard B. This shaft is provided with a crank, e, which receives the doublejointed pitman rod F, connected with the treadle G at g. The treadle is hinged to the tripod or stand, and is in line with the axis of the fly-wheel. Immediately over the fly wheel,and engaging with its upper beveled edge, and secured in a bearing attached to the standard B, is a beveled friction wheel or roller, H, of solid rubber, bushed with brass, pressed down to the fly-wheel by the spring 1. To this friction-wheel the continuousrotating rod or shaft K is secured, and keyed in a slotted sleevecoupling, 70, causing them to rotate together, and yet allowing the shaft to slide up and down freely to accommodate the change in its length in position during flexure. L designates a tubular staff or standard, supporting and protecting the shaft K. It is connected to the standard 13 by a rota-ting or sleeve joint provided with a set-screw, K, so as to allow or prevent motion at the will of the operator. Above this, at convenient distances, are arranged one or more hinged joints of peculiar construction, attached to staff L by rotating sleevejoints provided with set-screws, as at K. This joint is formed by two diverging branches, M M, firmly attached to the staff L, or to a collar, L, closely fitting either inside or outside of the staff L, allowing it to rotate freely. The upper part of the joint is formed of two similar branches, N, of the upper section, with holes for pivots to pass through, and extending downward a suitable distance below them to afford sufficient leverage for the springs or rubber rings .designed to keep the staff in an upright position when not in use. The two ends are 0011- nccted by an elongated ring, 0, embracing the staff; the object of this ring being to limit the amount of flexure, guard against accident in case the springs or rubber rings should be injured, and also to serve for the attachment of the springs or rubber rings P, which extend from the ring on either side of the staff, said springs or rubber rings being of equal strength, and so arranged as not to be affected by the rotation of the st-afi'; or these springs or rings might be attached directly to the branches N, and fastened, as shown, to the staif or sections. At each end of each section or length of the staff L, or at any convenient point between the two extreme ends, are arranged suitable bearings for the rod or shaft K, and at each joint the ends of the sections are connected by a universal or link joint. The several hinge-joints are properly balanced by springs of elastic rubber rings or other device so as to bend with each other, giving the engine great latitude of motion without interfering in the least with the rotation of the inclosed shaft, and at the same time giving it sufficient firmness for the purpose required. N ear the top of the staff, and attached to it by a collar so as to allow it to freely rotate around the staff L, is a short arm, S, curved upward and carrying in suitable bearings a short shaft, T. This shaft is designed to change the direction of the shaft K from a vertical to a horizontal position, and is connected with the vertical portion by a welltempered spiral spring, U. The other end is also fitted with a short length of spiral spring, to which is attached a steel rod, V, which transmits motion to the hand-piece. Attached to the arm S, over the spring uniting the shaft T to-the rod V, is pivoted an elastic fiat spring, X, through the free end of which the rod V passes. The object of this spring is to steady the rod and prevent the vibration-that would otherwise take place. This it does without interfering with its freedom of motion, and having the great advantage over a rigid arm that there is no danger by actual torsion to bend or throw it out of shape, for, being very sensitive to the slightest motion, it lends itself to any position or direction that is necessary for it to assume. It also guards the apparatus from injury if the hand-piece be allowed to fall suddenly, as may often happen in actual practice. At the top of the stafi', immediately above the arm S, is arranged a small stone, W, revolving with the shaft, designed for sharpening instruments, &c., and between the bearings of the shaft T a small grindstone may be suitably secured.

I have made an improvement in the mode of securing the tools in the hand-piece used with the machine, by which they are held securely, and are readily removed or changed without any risk to the tools or the socket in which they fit. This may be understood by reference to the drawing, in which a represents the revolving shaft fitted with a socket so as to-receive the tool I). At any convenient point of the socket a hole is drilled in the shaft at right angles to it, either entirely through or to the socket, as at 0 Into this a pin or point attached to the lever g fits snugly, said lever 9 being pivoted and arranged in a recess cut out of the shaft and held in position by the spring 0. At 6 an openin g is cut through the outer case 0 to allow the operator to press the lever down when wishing to remove his instrument. The tool is made with a depression or hole in the shank,-so situated that when it is in place the pin g will enter it and thus thoroughly key it in position,

and the beveled end of the burr or tool fits into a V-shaped opening or presses against the spring a, which prevents the tool from moving or twisting, and also takes the strain off the key-pin when the instrument is in operation. The great advantage of this arrangement, apart from its security and simplicity, is, that it does not cause any extra wear or friction upon the hand-piece or tools; while in use, the parts are absolutely at rest. The beveled end of the tool, when being pressed into place, raises the pin of the lever, the pin keying it so as to compel it to rotate with the shaft, and. holding it in place with slight pressure. At the opposite end of the shaft is fitted a spiral spring, 2, covered with a tube, 2, of rubber, leather, or other like material, so as to protect the patients mouth, clothing, or person from injury, said covering being arranged so as to rotate with the spiral spring which it incases.

The advantages of the various improvements herein described are briefly as follows: The foot-plate of the treadle and pitman being on different sides of the standard which gives bearings to the fly-wheel, the operators leg is not liable to come in contact with said pitman-an annoyance experienced with a different construction. The arrangement of the shaft K with its sleeve-coupling permits free rotation with the beveled wheel H, the spring I keeping said beveled wheel pressed well against the driving-wheel, while the key and slot in said coupling permit the shaft to slide up and down to accommodate itself to the fiexure at its joints. The means illustrated for changing the direction of the shaft from a vertical to a horizontal position, namely, the arm S, spring U, and short shaft T, possess great advantages. Were the spring alone employed, the change could, of course, be effected, but the shaft would lack the steadiness which my arrangement secures. This arrangement also affords, as described, a bearin g for a grindstone, which will often be found a very great convenience, and it enables me to effect the swiveled arrangement described, whereby the outer extremity of the arm may be turned easily around on the main shaft to any desired position, and keyed securely in place. The fiatmetal spring permits the horizontal portion or arm of the shaft to be easily raised or depressed, while it counteracts the tendency of the shaft to lateral vibration. The construction of the tool and hand-piece will also be found highly advantageous, as the tool when in place will be securely held, and yet may be easily removed when desired.

It is, of course, obvious that cogged wheels may be substituted for the friction drivingwheel and pinion. I prefer,.however, to employ the friction-wheels, as they work admirably, and are less noisy than cog-wheels; and though the universal joint is more costly than the spring-connection, and cannot be well employed where great flexure is necessary, still I prefer to use said universal joint, as the fiexurc necessary at the points indicated is but slight, and this form of joint, under such gircumstances, does not bind as the spring oes.

I have described means, including a spring or springs, for raising and holding the shaft in an upright position; but I do not claim, broadly, the employment of a spring for such purpose.

What I claim as my invention, and desire'to secure by Letters Patent, is-

1. The arrangement of the treadle-plate and pitman on opposite sides of the standard, said pitman and plate being connected by an arm of the latter intersecting the standard, substantially as described.

2. The combination of the wheel H, bearing B, shaf't K, and spring I, substantially as set forth.

3. The combination of the shaft K, slotted sleevecoupling 7c, and pin it, as shown and described.

4. The combination of the coupling M N with the staff L or the extensions thereof, the branches being attached to said staff L or to a collar or sleeve by suitable springs P P, as set forth.

5. In combination with the shaft K, the curved arm S, bent spring U, and short shaft T, as set forth.

6. The flat spring X, in combination with arm S and'rod V.

7. In combination with the rotating shaft of the hand-piece of a dental barring-engine, the sleeve e and burr or tool I), lever g,'pin g, and spring 0, said sleeve being provided with an opening, 6 for obtaining access to the spring 0, and-the burr or tool having one or more bevels at its shank end, as specified.

In testimony that I claim the foregoing I have hereunto set my hand.

CHARLES M. CURTIS.

Witnesses M. DANL. CONNOLLY, ALEXANDER HILLARY. 

